I appreciate the utility of the Artemis module to remove the complexity of soldering the Ambiq Apollo 3 chip+circuitry which allows for mere mortals to design PCBs that incorporate the module with their own needs. And then I noticed the pad layout which has hidden pads on the underside of the module. When this the module is certified, I understand an RF shield will cover the board. It seems to me that such a pad layout with RF shield means that it will be impossible to hand solder or hot air solder the interior pads.
My question is: what is the soldering process for incorporating the Artemis module onto a custom PCB board?
Hi Don, and thanks for your post.
Since the pads are ‘hidden’ underneath the board,the only way to solder the module would be to use a small dab of solder paste on each pad or use a stencil to apply solder paste to the pads. You’re not going to be able to get too the pads with a soldering iron but you could heat the bottom of your board with hot air to melt the paste and solder the module in place.
Some Bluetooth modules, and the and SARA4 are done in a similar fashion.
Thanks for the reply. I assume this works best for thinner (2 layer) boards which would have better thermal conductivity through the board. In addition, since clean up is not possible underneath, I assume this means no use of flux, and that no-clean paste is required. Am I correct?
You’d need less heat with a thin board, but thicker (multi layer) boards would work as well. It might just require more time to get the heat to soak all the way through the board or higher temperatures. When we run parts like the Artemis through our oven here, we increase the temperature for thicker boards to allow heat to get through the board and to the pads. The metal shield does block a bit of heat so it takes some trial and error do dial the temps in just right.
Yes, you would want to use no-clean paste on these. The flux in regular solder paste can be slightly conductive and since the bottom of the Artemis won’t be able to be cleaned you don’t want anything shorting out.